<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>第三页</title>
</head>
<body>
    <h1>我是第三页</h1>
    <button onclick="myback()">点我回退两页</button>
    <script>
        function myback(){
            history.go(-2);
            // console.log(history.length);
        }
        console.log(history.length);
    </script>
</body>
</html>